Fuente: Wipo "digitalization" The present disclosure provides a method (300) in a Base Band Unit, BBU, in a Digital Indoor System, DIS. The method (300) includes: allocating (310), to each of a plurality of digital headends in a cell, a Positioning Reference Signal, PRS, resource in such a manner that the PRS resources allocated to the plurality of digital headends are orthogonal to each other; and transmitting (320), to each of the plurality of digital headends, a PRS to be transmitted to a terminal device on the PRS resource allocated to the digital headend.